1. Field of the Invention
The present invention relates to a washer pump and more particularly to a washer pump of a simple construction which allows a driver to easily and reliably check the amount of cleaning liquid stored in a washer tank of an automobile.
2. Description of the Related art
Conventionally, in order check the amount of cleaning liquid stored in a washer tank and used by a window washer of a vehicle such as an automobile, a float 2 is placed in a washer tank 1 in order for a driver to examine the position of the float 2, as shown in FIG. 8.
However, according to the above-described construction, it is necessary to open the bonnet of an engine room provided with the washer tank 1 so as to check the position of the float. If a driver has not examined the position of the float 2 even through the amount of the cleaning liquid is very small, it will eventually happen that cleaning liquid is not supplied to the windshield even though the washer pump 3 operates.
In order to solve the above-described problem, examined Japanese Utility Model Publication No. 62-92427 discloses an apparatus as shown in FIG. 9. According to the apparatus, a level warning switch 6 which generates an electric signal upon detection of the amount of cleaning liquid is fixedly inserted into an opening 5a formed in a washer tank 5, and a warning lamp 7 which is turned on according to the electric signal generated by the switch 6 is provided in the vicinity of the driver's seat.
According to the above apparatus, the warning lamp 7 is turned on when the amount of cleaning liquid is less than a predetermined amount. Thus, the driver is informed that the amount of the cleaning liquid is small and can replenish the washer tank 5 with cleaning liquid without having to observe the cleaning liquid in the washer tank 5. That is, even though the driver has failed to check the amount of cleaning liquid, the situation does not arise in which cleaning liquid is not supplied to the windshield by the operation of the washer pump.
However, it is necessary to provide the apparatus with the switch 6, the warning lamp 7, and a wire harness for electrically connecting the switch 6 and the warning lamp 7 with each other. Consequently, the apparatus is complicated in its construction and is expensive.
Instead of the above-described means for electrically detecting the amount of cleaning liquid, Japanese Utility Model Laid-Open Publication No. 56-87959 discloses the following apparatus for automatically informing a driver of the reduction of cleaning liquid. The apparatus comprises a sub-tank having a large opening in an upper portion thereof and a small opening in a lower portion thereof connected with a pipe of a washer pump. According to this apparatus, when the amount of cleaning liquid in the washer tank has become small, the cleaning liquid is supplied to the sub-tank from only the lower opening. In this case, the cleaning liquid is intermittently jetted on the windshield. Thus, the driver can find that the amount of the cleaning liquid has become small.
However, it is necessary to fix the sub-tank to the bottom surface of the washer tank. As such, the washer tank needs to have a configuration suitable for accommodating the sub-tank and it takes time to mount the sub-tank in the washer tank. In addition, it is necessary to connect the sub-tank with the pipe of the washer pump, which takes time and labor and increases the number of parts.